The process of generating c# classes off the xsd is usually rather simple. One needs the xsd.exe utility (for example located here: C:\Program Files (x86)\Microsoft SDKs\Windows\v8.1A\bin\NETFX 4.5.1 Tools) and then a simple command to get things done:

xsd schema.xsd /c

Sometimes there may be some problems though with missing refs, namespaces and such.

In this example, I will generate classes for WMS 1.3.0 based on the OGC schemas - it is possible to grab them one by one, or all the goodies wrapped as a zip archive.

I have extracted WMS 1.3.0 schemas to f:\wms\schemas, so my command should look like this when in f:\wms (I have copied xsd.exe there too):

xsd schemas\capabilities_1_3_0.xsd /c

Unfortunately there are some problems and classes do not get generated:

The problem here is caused by unresolved references. Xsd was not able to find xlink.xsd. Although there is a xlink schema in OGC repo, this is not the one we're after. The one in question is the mentioned http://www.w3.org/1999/xlink, and its schema definition is http://www.w3.org/1999/xlink.xsd, pretty much as defined in the very beginning of the capabilities_1_3_0.xsd I am trying to process: